diff --git a/src/main.rs b/src/main.rs
index ecbc2cf..5932553 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,21 +1,54 @@
+use std::cmp::min;
+use std::collections::HashMap;
+
 struct Solution;
 impl Solution {
-    pub fn generate(num_rows: i32) -> Vec<Vec<i32>> {
-        let mut ans : Vec<Vec<i32>>= vec![vec![1]];
-        for i in 1..num_rows {
-            let mut row = vec![1];
-            let prev_row = &ans[(i - 1) as usize];
-            for j in 1..prev_row.len() {
-                row.push(prev_row[j - 1] + prev_row[j]);
-            }
-            row.push(1);
-            ans.push(row);
+    pub fn min_cost(basket1: Vec<i32>, basket2: Vec<i32>) -> i64 {
+        let mut map : HashMap<i32,i32> = HashMap::new();
+        let mut total_cost: i64 = 0;
+        let mut min_cost = i32::MAX;
+        for i in basket1.iter() {
+            *map.entry(*i).or_insert(0) += 1;
         }
-        ans
+        for i in basket2.iter() {
+            *map.entry(*i).or_insert(0) -= 1;
+        }
+        let mut kvs: Vec<(i32, i32)> = map.iter().filter(|(k, v)| {min_cost = min(min_cost, **k); if **v == 0 {false} else {true}}).map(|(k, v)| (*k, *v)).collect();
+        let mut err = false;
+        kvs.sort_by(|a, b| {
+            err |= b.1 % 2 == 1 || a.1 % 2 == 1;
+            if a.1 > 0 && b.1 < 0 {
+                std::cmp::Ordering::Greater
+            } else if a.1 < 0 && b.1 > 0 {
+                std::cmp::Ordering::Less
+            } else {
+                a.0.cmp(&b.0)
+            }
+        });
+        if err
+        { return -1; }
+        if kvs.is_empty() {
+            return 0;
+        }
+        let mut l = 0;
+        let mut r = kvs.len() - 1;
+        while l < r {
+            let cost = min( kvs[l].1.abs(), kvs[r].1.abs()) as i64;
+            total_cost += min(min(kvs[l].0, kvs[r].0) as i64 * cost / 2,min_cost as i64 * cost);
+            kvs[l].1 += cost as i32;
+            kvs[r].1 -= cost as i32;
+            if kvs[l].1 >= 0 {
+                l+=1;
+            }
+            if kvs[r].1 <= 0 {
+                r-=1;
+            }
+        }
+        if kvs[l].1 > 0 || kvs[r].1 > 0 { -1 } else { total_cost }
     }
 }
 
 fn main() {
-    let sl = Solution::generate(7);
+    let sl = Solution::min_cost(vec![4,2,2,2], vec![1,4,1,2]);
     println!("{:?}", sl);
 }